When you are really distracted during prayer
This type of prayer isn't supposed to take the place of verbal prayer. It is an additional form of prayer to add to what should be an ever-expanding variety of forms of prayer we use with God (for a comprehensive list of forms of Christian prayer, see Richard Foster, Prayer: Finding the Heart's True Home).
At Sanctuary Church, we are practicing 40 Days of Listening Prayer during the season of Lent (see the prayer blog here). Today Laura Jenkins, the host of the prayer blog, asked, "During your journey so far, have you felt God pulling you toward ways of growing deeper in your relationship with Him that weren’t what you expected, or that feel uncomfortable?" Here are some thoughts I wrote in response.
In answer to your question about the journey so far, I have had some really distracting days lately, when it has been tough to establish very much inner peace and quietness. Those have been uncomfortable days. I have been helped by a point made by Thomas Keating: sometimes the interior noise is so insistent that we find it almost impossible to settle down in God's presence. That doesn't mean it was a bad prayer time. If we are focused on just "being" in God's presence with him, we have to be content with giving God whatever we have to give him at that particular time. Thank you, Mr. Keating! That helps me relax.
To that point I would add that the times when we are most distracted but remain with God anyway might be the ones he values the most. It's like if we had two children, one of which was good natured and happy, and the other was emotionally impaired. When the first child says, "I love you," we would be filled with joy. But when the second child says, "I love you," we would hold that in our hearts as a unique treasure, knowing love was expressed in spite of great obstacles.